Which Android platform and API to target?

I'm just about to launch my first Android app, and it runs on the Android 1.1 platform, API Level 2, but is this what I should officially sign and launch the app as? Does it affect performance at all or is it simply for Android to know which devices it works on?

The only problem I see is that I can't specify <supports-screens> in the Manifest, which I would like to do, but it appears I'd have to launch at 1.6 at least for this to work.

Would I be missing a huge number of phones b开发者_开发问答y launching at 1.6 instead of 1.1?

Thank you!

Removing out of date info and info that I'm sure will be out of date in the near future. Just go here to see what versions you should care about:

http://developer.android.com/resources/dashboard/platform-versions.html

I'd say 1.5 is a good choice for now. Have a look at the chart here: http://android-developers.blogspot.com/2009/12/knowing-is-half-battle.html

Recent update of the Android fragmentation from Android Tapp:

Android fragmentation http://www.androidtapp.com/wp-content/uploads/2010/05/Finally-More-Users-on-Android-2.1-but-Android-Still-Fragmented-Chart.jpg

As far as I am concerned, I start developing targeting 1.5. When half finished, I would switch to 2.1 and when finished, I would try all versions in-between. I do not regard it necessary to mind any version lower 1.5 ... you cannot be downward compatible to the beginning of the universe ;-)

Strategies for Legacy Applications http://developer.android.com/guide/practices/screens_support.html#strategies